ALS, PHi: Gratz Collection; Sprague transcript, DLC:GW. Mercer’s addressed cover, which includes the notation “By Mr Ross,” is in DNA: RG 93, Manuscript File, 21617. It is docketed “Genl Mercers Letter. Elizabeth Town 18th July 1776” in Samuel Blachley Webb’s writing. The front and reverse of the ALS contain a biographical sketch of Mercer written sometime after his death by his aide-de-camp John Armstrong, Jr.

Mercer apparently enclosed with this letter a copy of his letter to Maj. Thomas Knowlton of this date, in which he writes: “You are to march your Party of three hundred Men to attack the Enemies Post at New Blazing Star—If possible have your Men near the Enemy before break of day, while you attempt to surprize the Enemy be careful that you are not discovered—have a small Guard advanced & if they come unexpectedly (on a Centinal) endeavour to seize his Arms & prevent giving an Alarm by firing, unless the Enemy is prepared & formidable—Let a Profound Silence be observed during the march & keep your Men in Indian file about one Pace assunder—If obliged to appear openly against the Enemy have some of your best Riflemen on your flanks, with orders to gain if possible the flanks of the Enemy—If they have Artillery a sudden Push is necessary to gain Possession of them—should you be succesful enough to take any of the British Troops Prisoners, secure them well & treat them with humanity—use the People on the Island with Civility unless they appear in Arms—as soon as it is light send out flanking Parties to secure you from surprize” (DLC:GW).